The CMB Infectious Disease Pathogenesis Section assisted Principal Investigators with experimental design, tissue collection and preparation, interpretation of histopathology findings, and assistance with manuscript preparation. CMB Research Support Specialists also provided technical expertise and support to NIAID Principal Investigators, assisting them with true cage to beachside support. Both pathology and technical proficiency resulted in numerous co-authorship opportunities. The CMB has completed the challenge of bringing a gnotobiotic facility on line. The gnotobiotic facility consists of 12 bio-exclusion units designed to keep the mice from becoming colonized with any adventitious microorganisms. Germ-free mice are free of all aerobic and anaerobic organisms with the possible exception of endogenous viruses. Breeding colonies and mice on study are maintained in semi-rigid isolators provided with HEPA-filtered air and autoclaved food, bedding, and supplies. Strict SOPs are followed to maintain the mice in a germ-free state. The CMB has an active Assisted Reproduction Technologies and Cryopreservation unit. Last year the ARTiC group banked 7052 embryos of 33 mouse lines from 10 different PIs. This year we have banked 1412 embryos of 12 lines and have 10 lines in the pipeline. Last year we froze the sperm of 57 mouse strains for 18 PIs, this year we froze the sperm of 32 lines for 16 different PIs. Last year for the Taconic project we 2981 embryos from 7 lines and 12 lines by sperm and this year we have 202 embryos from 1 line and 1 line by sperm cryopreservation. For another institute, we have frozen 34 lines by sperm cryopreservation and 7 by embryo cryopreservation. Last year we had 37 rederivations and we have 21 so far this year. Our unit is currently injecting 1 DNA construct and 2 embryonic stem cells. We still in research and development for guinea pig sperm cryopreservation and Siberian embryo transfer. We did also the first IVF with Thicket rats. A mission of the Comparative Medicine Branch (CMB) is to provide support to the emerging and re-emerging infectious disease research conducted within the NIAID/DIR Animal Biosafety Level (ABSL) 3 facilities. Members of the Comparative Medicine Branch (CMB) along with a Division of Occupational Health and Safety (DOHS) representative have submitted a manuscript to the Journal of the American Association for Laboratory Animal Science (JAALAS) providing a background of laws, regulations, and an overview of programmatic requirements pertaining to the use of Select Agents. The manuscript is currently under review.